MQ resins from stable ethylsilicate polymers

ABSTRACT

An MQ resin including at least 30% SiO 2 , preferably at least 50 wt % SiO 2 , and having dynamic viscosity of 50 centipoises (cps) to 750 cps at 25° C. is produced from a stable ethylsilicate polymer. The ethylsilicate polymer includes not greater than 1 wt % of TEOS monomer. The ethylsilicate polymer is produced by a two step addition of catalysts wherein a hydrolysis catalyst, for example, hydrochloric acid is added initially and a second catalyst, such as phosphonitrilic chloride trimer, is added subsequently.

This application is a continuation-in-part application of U.S. patentapplication Ser. No. 12/136,403, filed Jun. 10, 2008, which is herebyincorporated herein by reference in its entirety.

FIELD OF THE INVENTION

This invention relates to stable ethylsilicate polymers with 50 wt % ormore available silica (SiO₂) and not greater than 1 wt % monomer, andmethods of making such polymers, and more particularly to MQ resinsformed of the ethylsilicate polymer.

BACKGROUND FOR THE INVENTION

Tetraethyl orthosilicate is a major chemical compound with a formulaSi(OC₂H₅)₄. The compound is frequently abbreviated as TEOS and consistsof four ethyl groups attached to an SiO₄ ion that is referred to as anortho silicate. TEOS can also be considered to be the ethyl ester oforthosilicic acid, Si(OH)₄ and is a prototypical alkoxide. TEOS is atetrahedral molecule with many analogues, most of which are prepared byalcoholysis of silicon tetrachloride or the direct reaction of siliconmetal and ethanol.

Typically TEOS is hydrolyzed and condensed with mineral acid catalysts.TEOS is mixed with sufficient alcohol to allow its reactant water to bepartially miscible in the presence of an acid catalyst. This allows theinitial reaction to take place where one of the ethoxy groups isreplaced by a water molecule liberating ethanol as a by-product. This isillustrated by the following diagram:Si(OC₂H₅)₄+H₂O→(C₂H₅O)₃SiOH+C₂H₅OH

The condensation of silanol or triethoxysilanol (RO)₃SiOH, wherein R isC₂H₅, derived from the hydrolysis reaction is a competing reaction inthe presence of acid catalyst. This is illustrated by the followingdiagram:(C₂H₅O)₃SiOH+HOSi(OC₂H₅)₃→(C₂H₂O)₃SiOSi(OC₂H₅)₃+H₂O

Thus, the polymerization of TEOS with water in the presence of acatalyst results from sequential hydrolysis of ethoxy groups andcondensation of silanol in this over simplified view. In fact, there areother reactions, such as condensation of silanol with ethoxy groups thatprovide equivalent polymerization. All these processes result inpolymers of increasing complexity, variety in physical properties, andusefulness in their intended applications.

Typically these polymers are thought of as combinations of linear,cyclic and polycyclic polymers. Physical properties such as dynamicviscosity, viscosity stability, and available silica (SiO₂ wt %), aredependent on the amount of water reacted with the TEOS. This isexpressed as a percentage of the theoretical amount of water to replaceall the ethoxy groups bound to silicon. The stoichiometric amount ofwater is 2 moles of water to 1 mole of TEOS. This is referred to as 100%hydrolysis. When reacted with this amount of water, the resultingpolymer has the physical properties of amorphous silica. This can beobserved by reacting TEOS with 2 moles of water and then removing theby-product ethanol by distillation. What remains is a solid materialwith a high percentage of SiO₂ remaining in the composition, typically98% or higher. In practice it has been found that in order to obtainusable physical properties, such as a flowable liquid, only 40% of thetheoretical water is added and then the ethanol byproduct is removed.This results in a low viscosity liquid ethylsilicate polymer, orethylpolysilicate, that contains 40 wt % available SiO₂. The end productpolymer is considered to be a 40% hydrolyzed ethylsilicate polymer Thismaterial has become an item of commerce, known as SILBOND™ 40 orDynasil® 40.

TEOS also has many applications because of its easy conversion intoSiO₂. For example, it may be used for chemical mechanical polishing orthe synthesis of low molecular weight trimethylsiloxypolysilicates (MQResins) that are useful as additives for release coatings in pressuresensitive adhesive applications and liquid silicone rubber. The role ofMQ Resins in such formulations is to modify the properties of the curedsilicone rubber. The silicone rubber is hardened by the MQ resin to ahigher modulus. For pressure sensitive release applications MQ resinincreases the release forces of the adhesive. In both applications, thepresence of the low molecular weight MQ Resins is detrimental.

A further application for TEOS, where polymer distribution with reducedamounts of low molecular weight material are desired, relates to theformation of polysilicate binders for zinc rich coatings, investmentcasting, refractory, sand core, and ceramic articles in general. Adeveloping limitation for all these applications is the amount of lowboiling alcohol by-product, referred to as low boilers, liberated duringthe further hydrolysis of the ethylsilicate polymer. This raises theamount of volatile organic components (VOCs) present in the formulation.More environmentally friendly compositions are desired.

SUMMARY OF THE INVENTION

The invention provides an MQ resin produced from a stable ethylsilicatepolymer in liquid i.e. flowable form. The ethylsilicate polymer includesbetween 50 wt % to 60 wt % silica (SiO₂) and preferably between 53 wt %and 55 wt % silica (SiO₂) and has a dynamic viscosity of 10 centipoises(cps) to 1,000 cps at 25° C. The MQ resin maintains a dynamic viscosityof 50 cps to 750 cps at 25° C. for at least 2 months. Preferably, theethylsilicate polymer is essentially free or substantially free ofmonomer. More preferably, the ethylsilicate polymer is completely freeof monomer and remains in a flowable state for up to one year or more.

The invention also contemplates a process for making stableethylsilicate polymer in liquid or flowable form with between about 50wt % to about 60 wt % silica, a dynamic viscosity of 10 cps to 1000 cpsat 25° C., and including less than 1 wt % monomer. The method includesthe step of providing a mass of TEOS monomer, for example a condensedTEOS monomer including 28 wt % SiO₂, and hydrolyzing the TEOS monomerwith a hydrolyzing catalyst, for example a mineral acid. The method alsoincludes adding ethanol to the TEOS monomer with a mineral acidcatalyst. Then the mixture is heated to about 72° C. and acidified wateris added over a period of time. After completion of the water addition,a second catalyst step is performed, including adding a condensationcatalyst, for example a catalyst including 99 wt % of phosphoronitrilicchloride, such as a phosphoronitrilic chloride trimer. The mixture isstirred at reflux for about 2 hours and all of the alcohol is removed bydistillation.

The combination of a mineral acid catalyst and a PNC catalyst in a twostep process produces hydrolysis amounts up to about 90%, lower dynamicviscosity and an unusually high level of viscosity stability. It hasalso been found that the molecular distribution as indicated by gelpermeation chromatography is different. The difference is a narrowerdistribution that is shifted to smaller size molecules.

The invention will now be described in connection with the accompanyingdrawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart illustrating a process for making a stableethylsilicate polymer with 50% to 60% available SiO₂ by weight inaccordance with the present invention;

FIG. 2 is a graphical illustration showing the physical properties ofseveral examples of ethylsilicate polymers of the present invention;

FIG. 3 is a gel permeation chromatograph of a Prior Art 40% hydrolyzedsilicate polymer;

FIG. 4 is a gel permeation chromatograph of a 50% hydrolyzed silicatepolymer;

FIG. 5 is a gel permeation chromatograph of a 70% hydrolyzed polymercatalyzed with methansulfonic acid;

FIG. 6 is a gel permeation chromatograph of a 70% hydrolyzed polymercatalyzed with methansulfonic acid and a PNC catalyst;

FIG. 7 is a graphical illustration showing the physical properties offive respective runs made in accordance with another exampleethylsilicate polymer of the present invention; and

FIG. 8 is a graphical illustration showing a GPC of an MQ Resin.

DETAILED DESCRIPTION

A process for making a stable ethylsilicate polymer in liquid form withan available SiO₂ content of 50 wt % to 60 wt % will be described inconnection with FIG. 1. The stable ethylsilicate polymer has a dynamicviscosity of 50 cps to 70 cps at 25° C. and remains in liquid form for aperiod of about a year. The dynamic viscosity of the ethylsilicatepolymer is stable. For example, after heating the ethylsilicate polymerto 55° C. and maintaining the ethylsilicate polymer at that temperaturefor 20 days, the ethylsilicate polymer still has a dynamic viscosity at25° C. of less than 1000 cps.

The process includes the step 20 of providing a mass of TEOS, such as acondensed TEOS monomer including 28 wt % SiO₂, for example SILBOND™Condensed. Alternatively, the process can including providing anothermonomer including TEOS. The TEOS can be referred to astetra-ethyl-ortho-silicate or equivalently tetra-ethoxy-silane. The TEOSmonomer has the following structure:

A hydrolysis catalyst, such as a mineral acid, is added to the TEOS instep 22. For example, in a laboratory, the process included providing780 grams of TEOS monomer, and adding two drops of a mineral acidincluding 37 wt % HCl to the 780 grams of TEOS monomer. The hydrolysiscatalyst can include other types of mineral acids. In step 24, themethod includes adding to the mixture 10 wt. % to 12 wt. % ethanol,based on the total weight of the TEOS charge, or multiples of 125 gramsof ethanol. In the example, 125 grams of 200 proof ethanol were added.In step 26, the mixture is heated, for example to about 72° C. Then, instep 28, acidified water is added to the mixture, for example wateracidified with two drops of 37% HCl over a 1 hour time period. Toachieve 70% hydrolysis, the example process included adding 94.5 gramsof acidified water. To achieve 80% hydrolysis, the example includedadding 108 grams of water. A condensation catalyst, preferably a PNCcatalyst, such a phosphononitrilic chloride trimer, is introduced intothe mixture in step 30. The PNC catalyst can be another type of catalystincluding PNC. Preferably, the condensation catalyst includes PNC in anamount of at least 50 wt %, more preferably at least 70 wt %, even morepreferably at least 90 wt %, such as 99 wt %, based on the total weightof the PNC catalyst. In step 32 the mixture was stirred at reflux for aperiod of time, such as about 2 hours. In step 34, the ethanol wasremoved by heating. In this case, the temperature increased from 80° C.to about 140° C. over approximately three hours. In step 36, the ethanolwas collected by distillation and a clear stable silicate ester mixturewas recovered.

Examination of 40% hydrolyzed compositions reveals that they aredistributions of various individual components. For example, gaschromatography of the liquid material, which only separates volatilecomponents, shows that the material is a mixture of TEOS, dimer, trimer,tetramer and so forth. These linear structures have been characterizedby mass spectral analysis. This analysis method only separates volatilecomponents. Other methods, such as gel permeation chromatography, whichseparates components based on their molecular size, reveals morecomplicated distributions. TEOS polymers that are 40% hydrolyzed arecomplex mixtures ranging from lower oligomeric components such as dimer,trimer, and tetramer to more complicated cyclic and polycyclicstructures. The size of these components can range from thousands ofmolecular units to tens of thousands of molecular units.

As the hydrolysis amount is increased, the physical properties of theresulting polymer change. Increasing hydrolysis level to 50% hydrolysis,doubles dynamic viscosity, increases silica content to 45% and shiftsthe molecular weight distribution to higher molecular weight components.Viscosity stability becomes an increasingly important issue. Viscositystability is a function of the amount of uncondensed silanol remainingin the polymer structure. If the amount of silanol is too high, theviscosity of the resulting polymer increases with time, causingincreasing thickening of the polymer.

At hydrolysis amounts of 70% or higher, when using mineral acids ascatalyst, the dynamic viscosity and the viscosity stability of theresulting isolated polymer becomes impractical. This means that thepolymer does not flow properly and after standing for several days, thepolymer does not flow at all, becoming an intractable gelled mass.

When phosphonitrilic chloride is used at the hydrolysis amounts of 70%or higher, low dynamic viscosity polymers (50 cps) at 25° C. areproduced that show remarkable dynamic viscosity stability. The moleculardistribution as indicated by gel permeation chromatography is alsodifferent, specifically with the distributions being narrow and shiftedto smaller size molecules.

Further, an increase in hydrolysis % typically leads to a moreenvironmentally friendly process. For example, 40% hydrolyzedethylsilicate polymer releases 2.4 moles of ethanol per equivalent ofpolymer, a restricted VOC component, while a 70% hydrolyzedethylsilicate polymer releases only 1.2 moles of ethanol per equivalentof polymer, a 50% reduction.

The TEOS is typically hydrolyzed in an amount up to 90%. Thus, the endproduct of ethylsilicate polymer of the present invention is typicallyhydrolyzed in an amount up to 90%, preferably 75% to 85%.

As stated above, the end product of ethylsilicate polymer includes SiO₂in an amount of 50 wt % to 60 wt %. Alternatively, the ethylsilicatepolymer polymer includes SiO₂ in an amount of 52 wt % to 58 wt %. Theamount of SiO₂ in the ethylsilicate polymer polymer is determined byhydrolyzing and dehydrating the ethylsilicate polymer to a gelled statewith concentrated sulfuric acid. The gelled sample is treated with 70%nitric acid to oxidize the remaining organic components. The cruciblecontents are slowly burned off and the silica gel is fired in a mufflefurnace. The fired SiO₂ is then weighed to provide the wt % of SiO₂ inthe ethylsilicate polymer.

Phosphonitrilic chloride (PNC) comes in many forms. The most common ofwhich is cyclic trimer. This material is commercially available andproduces a low dynamic viscosity polymer. The prior art describesvarious linear phosphonitrilic chloride polymers which also work in anequivalent way.

The wt % of each component of the end product of ethylsilicate polymercan be determined by nuclear magnetic resonance (NMR). Further, gaspermeation chromatography can be used to separate components of theethylsilicate polymer according to their molecular size, based on theflow of the ethylsilicate polymer through a porous packing.

During the process of making the stable ethylsilicate polymer, as shownin FIG. 1, the TEOS monomer is hydrolyzed in an amount up to 90% andcondensed so that the stable ethylsilicate polymer produced is free,substantially free, or essentially free of monomer. As such, theethylsilicate polymer includes only traces of monomer to no monomer.Preferably, the final product ethylsilicate polymer includes no added orleft over monomer. For example, the ethylsilicate polymer can include atleast one monomer in an amount not greater than 1 wt %, more preferablynot greater than 0.5 wt %, even more preferably not greater than 0.1 wt%, and most preferably 0 wt %. As alluded to above, the ethylsilicatepolymer can include one or more monomers, but preferably the finishedproduct of ethylsilicate polymer includes no left over monomers, and assuch, only traces of monomer to no monomer would be present.

The monomer that could be present in the end product of ethylsilicatepolymer is TEOS monomer. As alluded to above, the ethylsilicate polymeris preferably free, substantially free, or essentially free of the TEOSmonomer. However, the ethylsilicate polymer could include the TEOSmonomer in an amount not greater than 1 wt %, preferably not greaterthan 0.5 wt %, even more preferably not greater than 0.1 wt %, and mostpreferably 0 wt %.

The TEOS monomer could have a low molecular weight component. Forexample, the monomer could have a molecular weight at peak (Mp) of 208.3g/mol, or not greater than 210 g/mol. The molecular weight at peak canbe referred to as the average molecular weight. The molecular weight ofthe ethylsilicate polymer and the components of the ethylsilicate can bedetermined by GPC.

Preferably, the ethylsilicate polymer is substantially free of linearoligomers. However, the ethylsilicate polymer could include at least onelinear oligomer in an amount not greater than 1 wt %, preferably notgreater than 0.5 wt %, more preferably not greater than 0.1 wt %, andmost preferably 0 wt %. As alluded to above, the ethylsilicate polymercould include one or more linear oligomers, but preferably theethylsilicate polymer includes no linear oligomers. At least one of thelinear oligomers could have a molecular weight at peak of 208.33 g/mol,or not greater than 210 g/mol.

Further at least one of the linear oligomers that could be present isselected from the group comprising a dimer, trimer, and tetramer.

The ethylsilicate polymer could include at least one dimer in an amountnot greater than 5 wt %, preferably not greater than 4 wt %, morepreferably not greater than 2 wt %, and most preferably 0 wt %. Thedimer could include hexaethoxydisiloxane. As alluded to above, theethylsilicate polymer could include one or more dimers, but preferablythe ethylsilicate polymer includes no dimer. At least one of the dimerscould have a molecular weight at peak of 342.5 g/mol, or not greaterthan 345 g/mol.

The ethylsilicate polymer could include at least one trimer in an amountnot greater than 20 wt %, preferably not greater than 16 wt %, and morepreferably not greater than 15 wt %. The trimers could include aphosphoronitrilic chloride trimer having a molecular weight at peak of347.66 g/mol, or not greater than 350 g/mol. The trimers could alsoinclude a linear TEOS trimer having a molecular weight of 476.7 g/mol,or not greater than 480 g/mol. The trimers could also include a cyclicTEOS trimer, having a molecular weight of 392.6 g/mol, or not greaterthan 480 g/mol. As alluded to above, the ethylsilicate polymer couldinclude one or more trimers, but preferably the ethylsilicate polymerincludes no trimer.

The ethylsilicate polymer could include at least one tetramer in anamount not greater than 20 wt %, preferably not greater than 16 wt %,and more preferably not greater than 15 wt %. The tetramers couldinclude a linear TEOS tetramer having a molecular weight at peak of610.9 g/mol, or not greater than 615 g/mol. The tetramers could alsoinclude a cyclic tetramer having a molecular weight of not greater than615 g/mol. As alluded to above, the ethylsilicate polymer could includeone or more tetramers, but preferably the ethylsilicate polymer includesno tetramers.

At least one of the oligomers could be a pentamer or a hexamer, whichare usually cyclic.

The ethylsilicate polymer is preferably free or essentially free ofsilanol. The ethylsilicate polymer could include not greater than 1 wt %silanol, based on the total weight of the ethylsilicate polymer,preferably not greater than 0.5 wt %, more preferably not greater than0.01 wt %, and most preferably 0 wt %.

The ethylsilicate polymer has a dynamic viscosity of from 10 cps to1,000 cps at 25° C., alternatively from 60 cps to 500 cps, or from 85cps to 300 cps at 25° C. The dynamic viscosity of the ethylsilicatepolymer can be measured according to the ASTM D 445-06 standard. Thedynamic viscosity is determined by measuring the time (in seconds)required for a standard volume of the liquid ethylsilicate polymer toflow through a calibrated capillary. The time is multiplied by theviscometer constant and the specific gravity of the ethylsilicatepolymer to provide the dynamic viscosity of the ethylsilicate polymer incps.

The kinematic viscosity at 25° C. of the ethylsilicate polymer ismeasured after heating the ethylsilicate polymer for a period of 20days,. The ethylsilicate polymer maintains a dynamic viscosity at 25° C.of 10 cps to 1,000 cps after heating the ethylsilicate polymer to atemperature of 55° C. for a period of 20 days. Alternatively, theethylsilicate polymer can maintain a dynamic viscosity at 25° C. of 60cps to 500 cps, or 85 cps to 410 cps, or 190 cps to 350 cps, afterheating the ethylsilicate polymer to a temperature of 55° C. for aperiod of 20 days.

Preferably, the ethylsilicate polymer has dynamic viscosity increase ofless than 300 cps at 25° C., after heating the after heating theethylsilicate polymer to a temperature of 55° C. for a period of 20days. The dynamic viscosity of the ethylsilicate polymer after beingheated for 20 days is compared to the dynamic viscosity of theethylsilicate polymer before heating. The low dynamic viscosity increaseafter heating indicates the dynamic viscosity of the ethylsilicatepolymer is stable. The ethylsilicate polymer does not form a gel afterheating to a temperature of 55° C. for a period of 20 days. The lowdynamic viscosity increase also indicates the ethylsilicate polymer willnot for a gel for at least 6 months at room temperature.

As stated above, the ethylsilicate polymer provides improved viscositystability. Preferably, the ethylsilicate polymer maintains a dynamicviscosity of from 10 cps to 1,000 cps at 25° C. for at least 4 months,more preferably at least 5 months, and most preferably at least 6months.

The molecular weight at peak (Mp), average molar mass (Mz), andpolydisparity of the ethylsilicate polymer can be determined byconventional GPC with refractive index detection. The molecular weightat peak (Mp) can be referred to as the average molecular weight.Preferably, the ethylsilicate polymer has an Mp of at least 34,600g/mol. Alternatively, the ethylsilicate polymer has an Mp of 33000 g/molto 35000 g/mol.

The ethylsilicate polymer preferably has an average molar mass (Mz) ofat least 107,000 g/mol. Alternatively, the ethylsilicate polymer has anMz of 400,000 g/mol to 600,000 g/mol. The Mz is determined dividing theweight average molecular weight of the ethylsilicate polymer by thenumber average molecular weight of the ethylsilicate polymer.

Preferably, the ethylsilicate polymer has a flash point of 75° F. to150° F. Alternatively, the ethylsilicate polymer has a flash point of80° F. to 130° F., or 88° F. to 118° F. The flash point of theethylsilicate polymer is measured according to the ASTM D 56-05standard.

Preferably, the ethylsilicate polymer has a specific gravity of 1.18g/cm³ to 1.26 g/cm³. Alternatively, the ethylsilicate polymer has aspecific gravity of from 1.19 g/cm³ to 1.24 g/cm³, or 1.20 g/cm³ to 1.22g/cm³. The specific gravity is measured according to ASTM D 891-09.

The color of the ethylsilicate polymer can be tested according to theplatinum-cobalt (Hazen) standards established by the American PublicHealth Association. It involves visual comparisons of a sample of theethylsilicate polymer with prepared standards in matched Nessler tubes.Preferably, the ethylsilicate polymer has a color of 15 to 60.Alternatively, the ethylsilicate polymer has a color of 18 to 55, or 20to 50.

The ethylsilicate polymer is free, substantially free, or essentiallyfree of low boilers, such as low boiling alcohol by-product that isliberated during hydrolysis of ethylsilicate polymer. The low boilingalcohol by-product content raises the amount of volatile organiccomponents (VOC) present in ethylsilicate polymer. The low boilers arefast evaporating solvent having a boiling point of 70 to 100° C.Preferably, the ethylsilicate polymer comprises low boilers in an amountnot greater than 5 wt %, more preferably 0.1 wt % to 3 wt %, and mostpreferably 0 wt %. The amount of low boilers is measured using GasLiquid Chromatography.

During the process of producing the ethylsilicate polymer, it isdesirable to limit the amount of VOCs generated, which can be collectedby distillation. The ethylsilicate polymer comprises not greater than 15wt % volatile material, based on the total weight of the ethylsilicatepolymer and the volatile material, more preferably not greater than 12wt %. The amount of volatile material of the ethylsilicate polymer ismeasured according to the ASTM D 2369-07 standard.

The ethylsilicate polymer preferably includes no HCl acid. However, theethylsilicate polymer could include HCl acid in an amount not greaterthan 0.1 wt %, based on the total weight of the ethylsilicate polymer,preferably not greater than 0.006 wt %. The amount of HCl can bemeasured by titrating a sample of the ethylsilicate polymer to theneutral red-methylene blue end point and then calculating the weightpercent of acidity or alkalinity.

The process of producing the ethylsilicate polymer includes replacingethoxy groups bound to silicon of the TEOS with water. This is expressedas a percentage of the theoretical amount of water to replace all theethoxy groups. The stoichiometric amount of water is 2 moles of water to1 mole of TEOS. This is referred to as 100% hydrolysis. Theethylsilicate polymer can be produced by a processes comprising 50% to60% hydrolysis of the TEOS. Alternatively, the ethylsilicate polymer isproduced by a process comprising 65% to 85% hydrolysis of the TEOS.

As alluded to above, the process of producing the ethylsilicate polymerincludes providing a mass of tetra TEOS monomer, such as tetra TEOSmonomer in a reactor, and adding ethanol to the TEOS monomer to form amixture. The method comprises adding a hydrolysis catalyst, such as amineral acid, to the mixture, followed by a condensation catalysts,preferably the PNC catalyst, such as a PNC trimer. The mixture isstirred and heated with the PNC catalyst while refluxing. The methodnext includes adding water to the mixture, recovering ethanol from themixture, and recovering an ethylsilicate polymer.

The method preferably includes hydrolyzing a mixture including TEOSmonomer and ethanol in the presence of a mineral acid, followed bycondensing the mixture with a PNC catalyst. Typically the methodincludes adding a hydrolysis catalyst, such as a mineral acid to theTEOS monomer, before adding the PNC catalyst. Examples of hydrolysiscatalysts include mineral acid, such as hydrochloric acid, sulfuricacid, nitric acid, boric acid, phosphoric acid, hydrofluoric acid, andhydrobromic acid. After adding the hydrolysis catalyst, the methodincludes adding water acidified with a mineral acid to form the mixture.The condensation catalyst is then added to the mixture and the ethanoland ethylsilicate polymer are recovered.

The following is an example of a preparation of the low dynamicviscosity ethylsilicate polymer that is produced using a two stepaddition of catalysts wherein one step includes adding a phosphonetrilicchloride catalyst.

INVENTIVE EXAMPLE 1

Production of Ethylsilicate Polymer Using PNC Catalyst

A 2 liter four necked round bottom flask, equipped with a centralstirrer, thermometer, Claisen take off adaptor, and addition funnel, ischarged with 780 grams of a condensed TEOS monomer including 28 wt %SiO₂, 2 drops of 37% HCl, and 125 grams of 200 proof ethanol. Themixture is heated to 72° C. To this hot stirring mixture is added 94.5grams of water acidified with 2 drops of 37% HCl over a period of 1hour. After completion of the addition of acidified water, 0.1 grams of99% phosphoronitrilic chloride trimer (PNC catalyst) was introduced. Themixture is stirred at reflux for 2 hours and then all ethanol wasremoved by heating. The temperature of the mixture increased from 80° C.to 140° C. over about 3 hours. Then, 530 grams of volatile material wascollected by distillation leaving 443 grams of a clear silicate estermixture. The clear ethyl polysilicate mixture was stable even afterheating at 55° C. for 20 days, showing only a modest increase in dynamicviscosity from 100 cps to 200 cps. This is indicative of stability inexcess of 6-12 months at room temperature.

The graph shown in FIG. 2 shows results of multiple runs as set forthabove.

COMPARATIVE EXAMPLE 1

Production of Ethylsilicate Polymer (No PNC Catalyst)

A 2 liter four necked round bottom flask, equipped with a centralstirrer, thermometer, Claisen take off adaptor, and addition funnel, ischarged with 780 grams of a condensed TEOS monomer including 28 wt %SiO₂, 0.1 grams of methansulfonic acid, 125 grams of 200 proof ethylalcohol. The mixture is heated to 76° C. To this hot stirring mixture isadded 94.5 grams of water over about 0.25 hours. The mixture is stirredat reflux for about 2 hours and then all ethanol was removed by heating.The temperature of the mixture increased from 80° C. to 140° C. overabout 3 hours. 558 grams of volatile material was collected bydistillation leaving 413 grams of a clear silicate ester mixture. Thissilicate ester mixture gelled on standing after 3 days.

Comparison of Molecular Distribution

Gel permeation chromatography separates molecular components accordingto size. By selecting a chromatography support with proper hole size,silicate oligomers are conveniently separated. This technique is usedfor quality control purposes for the production of 40% hydrolyzedethylsilicate polymer. The individual species are retained on theinstrument for longer time periods, depending on the molecular size ofeach species. In the series of components: TEOS, dimer, trimer, tetramerand higher homologs have decreasing retention times as the size of themolecule increases. A typical diagram for 40% hydrolyzed ethylsilicatepolymer is shown in FIG. 3. A progression of linear oligomers startingwith TEOS monomer with each of the higher homologs clearly separated isshown in FIG. 3. The distribution continues with multiple componentsforming a continuum of components of increasing molecular size but notseparated individually.

The diagram of FIG. 4 shows the distribution of 50% hydrolyzedethylsilicate polymer. In contrast to 40% hydrolyzed ethylsilicatepolymer, the amount of linear oligomers is reduced however each isclearly still present. The high molecular size components are increasein amount compared to the 40% hydrolyzed ethylsilicate polymerdistribution.

The distribution shown in FIG. 5 for 70% hydrolyzed polymer catalyzedwith methansulfonic acid shows reduced amounts of the shorter linearcomponents and a dramatically higher molecular weight distribution.Detectable levels of small linear components remain evident. Thisdistribution was unstable gelling after 3 days.

The distribution shown in FIG. 6 shows the molecular distribution thatarises from using a two step additional catalysts wherein one of thecatalysts is a phosphonitrilic chloride catalyst. In this distribution,low molecular weight oligomers are eliminated. In addition, the amountof high molecular size material is also reduced even though the observedsilica content was 54 wt % SiO₂. This material showed little change indistribution after 20 days stored at 55° C. This results in a moleculardistribution that is better suited for many applications ofethylsilicate polymers.

INVENTIVE EXAMPLE 2

Production of Ethylsilicate Polymer Using PNC Catalyst

A four necked 5 liter round bottom flask, equipped with a centralstirrer, thermometer, Claisen take off adaptor, and additional funnel,is charged with 3120 grams of a condensed TEOS monomer including 28 wt %SiO₂, 4 grams of PNCl₂, a PNC catalyst, prepared in Benzoyl ChlorideSolution, and 500 grams of SDA 29 denatured ethyl alcohol. The mixturewas heated to 80° C. To this hot stirring mixture was added 378 grams ofwater. HCl is introduced to the mixture via hydrolysis of the benzoylchloride when the water is added. The mixture is stirred at reflux for 2hours and then all ethanol was removed by heating. The temperature ofthe mixture increased from 80° C. to 140° C. over about 3 hours. Next,2300 grams of volatile materials were collected by distillation leaving1690 grams of a clear silicate ester mixture.

INVENTIVE EXAMPLE 3

Production of Ethylsilicate Polymer Using PNC Catalyst

A four necked 5 liter round bottom flask, equipped with a centralstirrer, thermometer, Claisen take off adaptor, and addition funnel, ischarged with 3120 grams of a condensed TEOS monomer including 28 wt %SiO₂, 0.4 grams of methansulfonic sulfonic acid (150 ppm), and 500 gramsof SDA 29 denatured alcohol. The mixture is heated to 80° C. To this hotstirring mixture is added 378 grams of water. After completion of theaddition of water, 0.4 grams of phosphonitrilic chloride trimer (PNCcatalyst) was introduced. The mixture is stirred at reflux for 2 hoursand then all ethanol was removed by heating. The temperature of themixture increased from 80° C. to 140° C. over about 3 hours. Next, 2253grams of volatile materials was collected by distillation leaving 1704grams of a clear silicate ester mixture. Five repeated runs gave thedata shown in FIG. 7.

COMPARATIVE EXAMPLE 3

Production of Ethylsilicate Polymer (No PNC2 Catalyst)

A four necked round bottom flask, equipped with a central stirrer,thermometer, Claisen take off adaptor, and addition funnel, is chargedwith 3120 grams of a condensed TEOS monomer including 28 wt % SiO₂, 0.5grams of methansulfonic acid, and 500 grams of SDA 29 denatured alcohol.The mixture is heated to 80° C. To this hot stirring mixture is added378 grams of water. The mixture is stirred at reflux for 2 hours andthen all ethanol was removed by heating. The temperature of the mixtureincreased from 80° C. to 140° C. over about 3 hours. Next, 2178 grams ofvolatile materials was collected by distillation leaving 1722 grams of aclear silicate ester mixture. This silicate ester mixture had a dynamicviscosity of 1188 cps and the mixture gelled on standing.

Zinc Coatings Produced from the Ethylsilicate Polymer

One application where polymer distributions with reduced amounts of lowmolecular weight material is desired relates to zinc rich coatings.Ethylsilicate polymers are a preferred binder for zinc dust forcorrosion resistant coatings. This is well documented in the prior art.The process of producing the ethylsilicate polymers used to form thezinc rich coatings includes replacing ethoxy groups bound to siliconwith water. This is expressed as a percentage of the theoretical amountof water to replace all the ethoxy groups. The stoichiometric amount ofwater is 2 moles of water to 1 mole of TEOS. This is referred to as 100%hydrolysis. The zinc rich coating can be produced by a processescomprising up to 90% hydrolysis, such as 50% to 90% hydrolysis.Alternatively, the zinc rich coating is produced by a process comprising75% to 85% hydrolysis.

The ethylsilicate polymer produced according to Inventive Example 3 canbe used to produce the coatings. One of the developing limitations forthis application is the amount of low boiling alcohol by-product that isliberated during hydrolysis of the ethylsilicate polymer. This raisesthe amount of volatile organic components present in the coatingformulation. Using more highly hydrolyzed ethylsilicate polymersprovides more environmentally friendly compositions that still meet therequirements of the marine coating industry. For a 40% hydrolyzedethylsilicate polymer, 74% of the mass potentially liberates ethanol,where as a 70% hydrolyzed polymer is only 53% of the mass is ethanol.This represents a 28% reduction in by-product ethanol.

Silicone Resin Produced from the Ethylsilicate Polymer

TEOS or ethylsilicate polymer is frequently used as a component insilicone resin technology. One skilled in the art is familiar with thevarious classes of resins and combinations of them. Some examples are TQresins, MQ resins, DQ resins, MQV resins, MQD resins, and DTQ resins Asignificant complication in resin production is the amount of ethanolliberated during hydrolysis and copolymerization when using TEOS as asource of tetrafunctional silicon (Q units). Furthermore achievingmolecular distributions that minimize or eliminate low molecular weightby-products such as tetrakistrimethylsilicate(neopentamer) areespecially desirable.

MQ resins are useful as additives for release coatings in pressuresensitive adhesive applications and liquid silicone rubber. The role ofMQ resins in these formulations is modification of physical propertiesof a finally cured silicone rubber. The silicone rubber is hardened bythis component to higher modulus. For pressure sensitive releaseapplication this increases the release force of the adhesive, thereforethe MQ resins are known “as control of release additives” causing therelease force to increase with increasing amounts of MQ resins. Inliquid silicone rubber, the presence of the MQ resin increases the shorehardness of the rubber is increased, which decreases the deformabilityof the rubber. In both applications, presence of low molecular weight MQresins is a detriment to the applications. In particular,tetrakistrimethylsiloxysilicate(neopentamer) causes significant issuewith silicone rubber formulations by introducing extractable lowmolecular species into the cured silicone rubber.

Preferably, the MQ resin is formed using the stable ethylsilicatepolymers of the invention, as described above. For example, the liquidMQ resin can be produced using the ethylsilicate polymer having amolecular weight distribution shown in FIG. 6, which is free of lowmolecular weight oligomers. Ethylsilicate polymers having less than 1 wt% low molecular weight oligomers, based on total weight of theethylsilicate polymer and a silica content of 50 wt % to 60 wt % arepreferred for the synthesis of the MQ resin. The MQ resin can be in aliquid form or a solid form. The compositions and characteristics of theMQ resins discussed in this application apply to both liquid MQ resinsand solid MQ resins, unless stated otherwise.

The end product of MQ resin is a silicone material, specifically atrimethylsiloxypolysilicate, including functional groups (CH₃)₃SiO (Mgroup) and SiO₄ (Q group). The MQ resin has the following structure:

Preferably, the end product of MQ resin has an M group to Q group ratioof 0.1 to 0.6. Alternatively, the MQ resin has an M group to Q groupratio of 0.4 to 0.5.

For example, the MQ resin can have an M group to Q group ratio of 0.2;and include the M group in an amount of 16.67 wt % and the Q group in anamount of 83.33 wt %, based on total weight of the MQ resin.

Alternatively, the MQ resin can have an M group to Q group ratio of 0.4;and include the M group in an amount of 25.57 wt % and the Q group in anamount of 71.43 wt %, based on total weight of the MQ resin.

Alternatively, the MQ resin can have an M group to Q group ratio of 0.6;and include the M group in an amount of 62.55 wt % and the Q group in anamount of 37.45 wt %, based on total weight of the MQ resin.

Preferably, the end product of MQ resin comprises SiO₂ in an amount of50 wt % to 60 wt %. Alternatively, the MQ resin comprises SiO₂ in anamount of 53 wt % to 55 wt %. The amount of SiO₂ in the liquid MQ resinis determined by hydrolyzing and dehydrating the MQ resin to a gelledstate with concentrated sulfuric acid. The gelled sample is treated with70% nitric acid to oxidize the remaining organic components. Thecrucible contents are slowly burned off and the silica gel is fired toSiO₂ in a muffle furnace. The fired SiO₂ is then weighted to provide thewt % of SiO₂ in the liquid MQ resin.

Preferably, the end product of MQ resin comprises the followingcomponents: ethylsilicate polymer comprising 50 wt % to 60 wt % SiO₂;ethyl alcohol (ETOH); water; methanesulfonic acid (CH₃SO₃H); toluene(C₇H₈ or C₆H₅CH₃); and hexamethyldisiloxane (HMDSO)(C₆H₁₈OSi₂). The wt %of each component of the MQ resin can be determined by nuclear magneticresonance (NMR). Further, gel permeation chromatography (GPC) can beused to separate components of the liquid MQ resin according to theirmolecular size, based on the flow of the liquid MQ resin through aporous packing.

Preferably, the end product of MQ resin includes the ethylsilicatepolymer comprising 50 wt % to 60 wt % SiO₂ content, or 55 wt % SiO₂, asdescribed above. Preferably, the MQ resin includes ethylsilicate polymerin an amount of at least 30 wt %, based on the total weight of the MQresin. Alternatively, the MQ resin includes ethylsilicate polymer in anamount of 30 wt % to 50 wt %, or 36 wt % to 44 wt %.

The end product of MQ resin typically includes an alcohol, such as ETOH,in an amount of 8 wt % to 15 wt %, or 10 wt % to 14 wt %.

The end product of MQ resin typically includes water in an amount of 5wt % to 10 wt %, or 6 wt % to 9 wt %.

The end product of MQ resin typically includes the methanesulfonic acid(CH₃SO₃H) in an amount of 0.001 wt % to 0.1 wt %, or 0.01 wt % to 0.07wt %.

The end product MQ resin typically includes the toluene in an amount of18 wt % to 35 wt %, or 22 wt % to 26 wt %.

The end product of MQ resin typically includes the HMDSO in an amount of18 wt % to 35 wt %, or 22 wt % to 26 wt %.

The end product of MQ resin typically includestetrakistrimethylsiloxysilicate (neopentamer) in an amount not greaterthan 5 wt %, or not greater than 1 wt %. or 0.01 wt % to 5 wt %.

The molecular weight at peak (Mp), average molar mass (Mz), andpolysipersity of both the liquid and solid MQ resins can be determinedby conventional GPC with refractive index detection.

As stated above, the MQ resin for use in silicone rubber applicationspreferably has a high molecular weight. The end product of MQ resin canbe in liquid form and have a molecular weight at peak (Mp) of at least33,000 g/mol, or 33,000 g/mol to 36,000 g/mol, or 34,000 g/mol to 35,000g/mol. For example, the liquid MQ resin can have an average molecularweight at peak (Mp) of 35,000. The molecular weight at peak (Mp) can bereferred to as the average molecular weight.

The liquid MQ resin typically has an average molar mass (Mz) of at least400,000 g/mol, or 400,000 g/mol to 600,000 g/mol, or 500,000 g/mol to600,000 g/mol. For example, the liquid MQ resin can have an averagemolar mass (Mz) of 535,000 g/mol.

The liquid MQ resin typically has a polydisparity of 6 to 10, or 7.2 to9.4. For example, the liquid MQ resin can have a polydisparity of 8.3.

The MQ resin can also be in solid form and have a molecular weight atpeak (Mp) of at least 34,000 g/mol, or of 34,000 g/mol to 36,000 g/mol.For example, the liquid MQ resin can have an average molecular weight atpeak (Mp) of 34,600.

The solid MQ resin typically has an average molar mass (Mz) of at least90,000 g/mol, or 90,000 g/mol to 110,000 g/mol. For example, the solidMQ resin can have an average molar mass (Mz) of 107,000 g/mol. Theaverage molar mass (Mz) is determined dividing the weight averagemolecular weight of the MQ resin by the number average molecular weightof the MQ resin.

The solid MQ resin typically has a polydisparity of 2 to 4, or 2.3 to3.2. For example, the solid MQ resin can have a polydisparity of 2.8.

As alluded to above, the ethylsilicate polymer used to produce the MQresin is free, essentially free, or substantially free of monomer, suchas TEOS monomer. Thus, the end product of MQ resin is free, essentiallyfree, or substantially free of monomer. Preferably, the MQ resinincludes monomer in an amount not greater than 1 wt %, more preferablynot greater than 0.5 wt %, even more preferably not greater than 0.1 wt%, and most preferably 0 wt %.

As alluded to above, the end product of MQ resin preferably includes nolow boilers, such as low boiling alcohol by-product, liberated duringhydrolysis of the ethylsilicate polymer. The low boiling alcoholby-product (low boilers) content raises the amount of volatile material,such as volatile organic components (VOC) present in the MQ resin.Preferably, the MQ resin includes low boilers in an amount less than 2.5wt %, based on the total weight of the MQ resin and the low boilers. TheMQ resin could include low boilers in an amount of 0.1 wt % to 2.5 wt %.The amount of low boilers is measured using Gas Liquid Chromatography.

During the process of producing the ethylsilicate polymer used toproduce the MQ resin, it is desirable to limit the amount of volatilematerial (VOC) produced, which can be collected by distillation. Theprocess of producing the MQ resin preferably includes generating notgreater than 15 wt % volatile material, based on the total weight of theMQ resin and the volatile material, preferably not greater than 12 wt %.For example, the process could include generating 1 wt % to 12 wt %volatile material, based on the total weight of the MQ resin and thevolatile material. The amount of volatile material of the MQ resin ismeasured according to the ASTM D 2369-07 standard.

The end product of MQ resin preferably includes no HCl acid. The MQresin could include HCl acid in an amount not greater than 0.1 wt %,based on the total weight of the MQ resin, and preferably not greaterthan 0.006 wt %, based on the total weight of the MQ resin. The amountof HCl can be measured by titrating a sample of the MQ resin to theneutral red-methylene blue end point and then calculating the weightpercent of acidity or alkalinity.

The liquid MQ resin typically has a dynamic viscosity of 50 cps to 750cps at 25° C., or 50 cps to 55 cps at 25° C. The dynamic viscosity isdetermined by measuring the time (in seconds) required for a standardvolume of the liquid MQ resin to flow through a calibrated capillary.The time is multiplied by the viscometer constant and the specificgravity of the liquid MQ resin to provide the dynamic viscosity of theliquid MQ resin in cps.

As alluded above, the liquid MQ resin provides improved viscositystability. Preferably, the liquid MQ resin maintains a dynamic viscosityof from 50 cps to 750 cps at 25° C. for at least 2 months, morepreferably at least 3 months.

Preferably, the liquid MQ resin has a flash point of at least 100° F.,more preferably at least 110° F. The flash point of the liquid MQ resinis measured according to the ASTM D 56-05 standard.

The MQ resin typically has a specific gravity of from 1.14 g/cm³ to 1.25g/cm³. Alternatively, the MQ resin has a specific gravity of from 1.16g/cm³ to 1.24 g/cm³, or 1.19 g/cm3 to 1.22 g/cm³. The specific gravityis measured according to ASTM D 891-09.

As alluded to above, in the process of producing the MQ resin, it isdesirable to limit the amount of ethanol liberated during hydrolysis andthus the amount of low boilers. The amount of ethanol generated duringthe process is determined by the following formula:wt % ethanol generated=2×molar mass of ethanol×H₂O Added (wt %)/molarmass of H₂O

As stated above, the process includes liberating the ethanol generatedduring hydrolysis. Preferably, the process of producing the MQ resincomprises liberating ethanol in an amount not greater than 70 wt %, morepreferably not greater than 60 wt %, and most preferably not greaterthan 35 wt %.

As stated above, the process of producing the ethylsilicate polymersused to form the MQ resin includes replacing ethoxy groups bound tosilicon of the TEOS monomer with water. This is expressed as apercentage of the theoretical amount of water to replace all the ethoxygroups. The stoichiometric amount of water is 2 moles of water to 1 moleof TEOS. This is referred to as 100% hydrolysis. The MQ resin istypically produced by a processes comprising 50% to 90% hydrolysis ofthe TEOS monomer, or 75% to 85% hydrolysis of the TEOS monomer.

The GPC traces shown in FIGS. 5 and 6 compare MQ Resins from 40%hydrolyzed ethylsilicate polymer and from MQ Resins prepared from anexample stable ethylsilicate polymer of the present invention, PNCcatalyzed ethylsilicate polymer including 55 wt % SiO₂. As is seen inthe diagrams, the amount of low size material below 16 minute retentiontime for the is negligible, where the amount of low size material in the40% hydrolyzed polymer is substantially more. This is an indication thatmigratory material present in the polymer distribution will be favorablyreduced, by using the product of the present invention as a startingmaterial.

The MQ resin is produced by a process comprising mixing the stableethylsilicate polymer, as described above, with alcohol and a hydrolysiscatalyst, such as methansulfonic acid. The process next includes heatingthe mixture to a temperature of 80° C. and adding water to the mixture.The mixture is stirred at reflux and then toluene andhexamethyldisiloxane are added. The volatile material is removed toprovide the MQ resin.

Preparation of Resins that Include Q Units

The example below illustrates the utility of these new moleculardistributions. As discussed above, MQ resins are silicate resins thathave utility in silicone elastomers and pressure sensitive adhesives. Akey measurement of the quality of these resins is the average molecularweight and content of tetrakistrimethylsilylsilicate. The followingrepresents an example of the advantages of producing these resins withthe ethylsilicate polymers described in this invention.

INVENTIVE EXAMPLE 4

Production of MQ Resin from Ethylsilicate Polymer

A four necked round bottom flask, equipped with a central stirrer,thermometer, Claisen take off adaptor, and addition funnel, is chargedwith 835 grams of ethylsilicate polymer including 55 wt % SiO₂, 0.5grams of methansulfonic acid, and 250 grams of SDA 29 denatured alcohol.The ethylsilicate polymer has the properties described above and is madeaccording to the process shown in FIG. 1. The mixture is heated to 80°C. To this hot stirring mixture is added 155 grams of water. The mixtureis stirred at reflux for 2 hours and then 500 grams of toluene, 324grams of hexamethyldisiloxane are added. 800 grams of volatile materialwas removed to produce a 50% solids solution of MQ resin in solution. Asample of the MQ resin is provided in powder form and analyzed by gelpermeation chromatography. Analysis of the MQ resin by gel permeationchromatography produced the following molecular distributions:

Sample Mp Mn Mw Mz PD MQ resin 34600 18000 51100 107000 2.8

The molecular distributions of the MQ resin produced showed notrimethylsilylated species and substantially higher molecular weightthan the MQ resins reported in literature. An article in the J. ApplPolym Sci 70: 1753-1757, 1998 reported molecular weights of 4200 to 4956and molecular distributions that indicated a large peak at longretention time, indicating the presence of low molecular weighttrimethylsilylated species such as tetrakistrimethylsilylsilicate.

INVENTIVE EXAMPLE 5

Composition of MQ Resin from Ethylsilicate Polymer

A liquid MQ resin is formed from hydrolyzed ethylsilicate polymerincluding 50 wt % SiO₂. The liquid MQ resin has an M group to Q groupmole ratio of 0.4. The MQ resin comprises 40.45 wt % ethylsilicatepolymer; 12.1 wt % ETOH; 7.5 wt % water; 0.04 wt % methane sulfonicacid; 24.22 wt % toluene; and 15.69 wt % HMDSO.

While the invention has been described in connection with its preferredembodiments it should be recognized that changes and modifications maybe made therein without departing from the scope of appended claims.

The invention claimed is:
 1. An MQ resin, in solid or liquid form,comprising hexamethyldisiloxane (C₆H₁₈OSi₂) in an amount of 18-35 wt %of the MQ resin and an ethylsilicate polymer, wherein said ethylsilicatepolymer has a dynamic viscosity of 10 csp to 1000 cps at 25° C. andincludes from 50 wt % to 60 wt % silica (SiO₂), and wherein saidethylsilicate polymer has less than 1 wt % monomers, based on the totalweight of said ethylsilicate polymer, and said MQ resin furthercomprising alcohol in an amount of 8 wt% to 15 wt % based on the totalweight of said MQ resin.
 2. An MQ resin, in solid or liquid form,comprising hexamethyldisiloxane (C₆H₁₈OSi₂) in an amount of 18-35 wt %of the MQ resin and an ethylsilicate polymer, wherein said ethylsilicatepolymer has a dynamic viscosity of 10 csp to 1000 cps at 25° C. andincludes from 50 wt % to 60 wt % silica (SiO₂), and wherein saidethylsilicate polymer has less than 1 wt % monomers, based on the totalweight of said ethylsilicate polymer, and said MQ resin furthercomprising water in an amount of 5 wt % to 10 wt % based on the totalweight of said MQ resin.
 3. An MQ resin in solid or liquid form,comprising hexamethyldisiloxane (C₆H₁₈OSi₂) and an ethylsilicatepolymer, wherein said ethylsilicate polymer has a dynamic viscosity of10 csp to 1000 cps at 25° C. and includes from 50 wt % to 60 wt % silica(SiO₂), and wherein said ethylsilicate polymer has less than 1 wt %monomers, based on the total weight of said ethylsilicate polymer andwherein the MQ resin has a M group to Q group ratio of 0.1 to 0.6,wherein said M group is (CH₃)₃SiO and said Q group is SiO₄.
 4. The MQresin of claim 3 including SiO₂ in an amount of 53 wt % to 55 wt % ofthe ethylsilicate polymer.
 5. The MQ resin of claim 3 having less than 1wt % tetrakistrimethylsiloxysilicate (neopentamer) of the MQ resin. 6.The MQ resin of claim 3 having less than 1 wt % of the MQ resin of atleast one linear oligomer.
 7. The MQ resin of claim 3 including at least30 wt % of the MQ resin of said ethylsilicate polymer.
 8. The MQ resinof claim 3 including at least 40 wt % of the M Q resin of saidethylsilicate polymer.
 9. The MQ resin of claim 3 including ethylalcohol, water, methanesulfonic acid, and toluene.
 10. The MQ resin ofclaim 3 in liquid form and having a dynamic viscosity of 50 cps to 750cps at 25° C.
 11. The MQ resin of claim 10 maintaining a dynamicviscosity of 50 cps to 750 cps at 25° C. for at least 2 months.
 12. TheMQ resin of claim 3 in liquid form and having a molecular weight at peak(Mp) of 33,000 g/mol to 35,000 g/mol.
 13. An MQ resin in solid or liquidform, comprising hexamethyldisiloxane (C₆H₁₈OSi₂) and an ethylsilicatepolymer, wherein said ethylsilicate polymer has a dynamic viscosity of10 csp to 1000 cps at 25° C. and includes from 50 wt % to 60 wt % silica(SiO₂), and wherein said ethylsilicate polymer has less than 1 wt %monomers, based on the total weight of said ethylsilicate polymer andwherein the MQ resin is in liquid form and having an average molar mass(Mz) of 400,000 g/mol to 600,000 g/mol.
 14. The MQ resin of claim 13 insolid form and having a molecular weight at peak (Mp) of 34,000 g/mol to36,000 g/mol.
 15. The MQ resin of claim 3 in liquid form and having aspecific gravity of 1.14 g/cm³ to 1.25 g/cm³.
 16. An MQ resin in solidor liquid form, comprising hexamethyldisiloxane (C₆H ₁₈OSi₂) and anethylsilicate polymer, wherein said ethylsilicate polymer has a dynamicviscosity of 10 csp to 1000 cps at 25° C. and includes from 50 wt % to60 wt % silica (SiO₂), and wherein said ethylsilicate polymer has lessthan 1 wt % monomers, based on the total weight of said ethylsilicatepolymer and wherein the MQ resin is in liquid form and having apolydispersity of 6 to
 10. 17. The MQ resin of claim 3 including HClacid in an amount less than 0.1 wt % of the MQ resin.
 18. The MQ resinof claim 3, wherein said ethylsilicate polymer is produced by a processcomprising adding a PNC catalyst to a mixture including a TEOS monomerand ethanol.
 19. The MQ resin of claim 18 wherein said process includesadding a hydrolysis catalyst to said mixture before adding said PNCcatalyst.
 20. The MQ resin of claim 3 produced by a process comprising50% to 90% hydrolysis of a TEOS monomer.
 21. An MQ resin of claim 3produced by a process comprising generating not greater than 2.5 wt %low boiling alcohol by-product having a boiling point of 70° C. to 100°C., based on the total weight of said MQ resin and said low boilingalcohol by-product.
 22. The MQ resin of claim 3 produced by a processcomprising generating not greater than 15 wt % volatile material, basedon the total weight of said MQ resin and said volatile material.
 23. TheMQ resin of claim 3 produced by a process comprising generating notgreater than 70 wt % ethanol of the MQ resin.
 24. The MQ resin of claim13, wherein said ethylsilicate polymer is produced by a processcomprising adding a PNC catalyst to a mixture including a TEOS monomerand ethanol.
 25. The MQ resin of claim 24 wherein said process includesadding a hydrolysis catalyst to said mixture before adding said PNCcatalyst.
 26. An MQ resin of claim 3 produced by a process comprisinggenerating not greater than 2.5 wt % low boiling alcohol by-producthaving a boiling point of 70° C. to 100° C., based on the total weightof said MQ resin and said low boiling alcohol by-product.
 27. The MQresin of claim 3 produced by a process comprising generating not greaterthan 15 wt % volatile material, based on the total weight of said MQresin and said volatile material.
 28. The MQ resin of claim 3 producedby a process comprising generating less than 70 wt % ethanol of the MQresin.
 29. An MQ resin in solid or liquid form comprising a stableethylsilicate polymer in an amount of at least 30 wt % of the MQ resin,wherein said stable ethylsilicate polymer includes from 50 wt % to 60 wt% silica (SiO₂), less than 1 wt % of at least one monomer of said stableethylsilicate polymer, and has a dynamic viscosity of 10 csp to 1000 cpsat 25° C.; and wherein said MQ resin includes alcohol in an amount of 8wt % to 15 wt % of the MQ resin, water in an amount of 5 wt % to 10 wt %of the MQ resin, methanesulfonic acid (CH₃SO₃H) in an amount not greaterthan 0.1 wt % of the MQ resin, toluene in an amount of 18 wt % to 35 wt% of the MQ resin, and hexamethyldisiloxane in an amount of 18 wt % to35 wt % of the MQ resin.
 30. An MQ resin in liquid form comprising: astable ethylsilicate polymer in an amount of at least 30 wt % of the MQresin, wherein said stable ethylsilicate polymer includes from 50 wt %to 60 wt % silica (SiO₂), not greater than 1 wt % of at least onemonomer, and has a dynamic viscosity of from 10 csp to 1000 cps at 25°C.; alcohol in an amount of 8 wt % to 15 wt % of the MQ resin; water inan amount of 5 wt % to 10 wt % of the MQ resin; methanesulfonic acid(CH₃SO₃H) in an amount not greater than 0.1 wt % of the MQ resin;toluene in an amount of 18 wt % to 35 wt % of the MQ resin;hexamethyldisiloxane in an amount of 18 wt % to 35 wt % of the MQ resin;an M group to Q group ratio of 0.1 to 0.6; not greater than 1 wt % of atleast one monomer of the MQ resin; not greater than 1 wt %tetrakistrimethylsiloxysilicate (neopentamer) of the MQ resin; notgreater than 1 wt % of the MQ resin of at least one linear oligomer; HClacid in an amount not greater than 0.1 w t% of the MQ resin; a dynamicviscosity of 50 cps to 750 cps at 25° C.; a molecular weight at peak(Mp) of 33,000 g/mol to 35,000 g/mol; an average molar mass (Mz) of400,000 g/mol to 600,000 g/mol; a specific gravity of 1.14 g/cm³ to 1.25g/cm³; and a polydisperity of 6 to
 10. 31. An MQ resin in solid formcomprising: a stable ethylsilicate polymer in an amount of at least 30wt % of the MQ resin, wherein said stable ethylsilicate polymer includesfrom 50 wt % to 60 wt % silica (SiO₂), not greater than 1 wt % of atleast one monomer, and has a dynamic viscosity of from 10 csp to 1000cps at 25° C.; alcohol in an amount of 8 wt % to 15 wt % of the MQresin; water in an amount of 5 wt % to 10 wt % of the MQ resin;methanesulfonic acid (CH₃SO₃H) in an amount not greater than 0.1 wt % ofthe MQ resin; toluene in an amount of 18 wt % to 35 wt % of the MQresin; hexamethyldisiloxane in an amount of 18 wt % to 35 wt % of the MQresin; an M group to Q group ratio of 0.1 to 0.6; not greater than 1 wt% tetrakistrimethylsiloxysilicate (neopentamer) of the MQ resin; notgreater than 1 wt % of the MQ resin of at least one linear oligomer; HClacid in an amount not greater than 0.1 wt % of the MQ resin; a dynamicviscosity of 50 cps to 750 cps at 25°0 C.; a molecular weight at peak(Mp) of 33,000 g/mol to 35,000 g/mol; an average molar mass (Mz) of90,000 g/mol to 111,000 g/mol; a specific gravity of 1.14 g/cm³ to 1.25g/cm³; and a polydisperity of 2 to
 4. 32. The MQ resin of claim 13,wherein said ethylsilicate polymer is produced by a process comprisingadding a PNC catalyst to a mixture including a TEOS monomer and ethanol.33. The MQ resin of claim 32 wherein said process includes adding ahydrolysis catalyst to said mixture before adding said PNC catalyst.